10 Best Window Ac Heater Units 2026 in the United States

The Keystone 18,800 BTU Window-Wall Air Conditioner and Heater is designed to provide year-round comfort for large spaces up to 1,000 sq. ft. It boasts a substantial 18,000 BTU cooling capacity and a 16,000 BTU supplemental heating capacity, making it suitable for both hot summers and chilly winters. The unit also includes a dehumidifier and fan circulation, enhancing its versatility. However, the heating function is supplemental and not intended as the primary heat source, which could be a limitation in extremely cold weather. The device features a smart remote that senses room temperature and adjusts the cooling accordingly, adding convenience and energy efficiency.

The Energy Efficiency Ratio (EER) of 10.7 indicates moderate efficiency. While it does offer energy-saving modes like 'Energy Saver' and 'Sleep,' it is not Energy Star certified, which might be a concern for energy-conscious users. The noise level of 55 dB is relatively low for a unit of this capacity, making it a good choice for living rooms and apartments where noise could be an issue. The included window installation kit and the option to install it through the wall make it flexible when it comes to installation, although its size and weight (117.3 pounds) might require some effort and planning.

Additional features like remote control, filter light reminder, and a 4-way swing add to its user-friendly design. This Keystone unit is a powerful and versatile option for large rooms, offering both heating and cooling capabilities, though it may not be the most energy-efficient choice on the market.

The Whirlpool 18,000 BTU window air conditioner is a solid choice for cooling and supplemental heating in rooms up to 1,000 square feet, making it suitable for apartments, living rooms, or bedrooms of medium to large size. Its strong cooling power is complemented by a supplemental heating feature rated at about 10,600 BTU, which is handy for mildly chilly days but not intended as a main heat source during very cold months.

With a Seasonal Energy Efficiency Ratio (SEER) of 10.7 and an Energy Star rating of 1 star, it offers moderate energy efficiency—good, but not the highest in its class. Noise level sits at 56 dB, which is fairly typical for a unit this size; it’s noticeable but shouldn’t be too disruptive for most users. Installation is straightforward thanks to the included mounting kit, designed for windows at least 19.5 inches tall, and the unit’s size and weight (about 109 pounds) mean you may need some help putting it in place.

Additional features like a reusable dust filter, remote control, 24-hour programmable timer, and multiple cooling speeds add convenience and help maintain air quality. On the downside, the heating capacity is limited and the unit’s energy efficiency leaves room for improvement, so if you’re looking to use it as a main heater or want the most cost-effective option, you might want to consider other models. It balances powerful cooling with useful heat support and easy controls, making it a versatile option for those needing both heating and cooling in one window-mounted device.

The LG 24,500 BTU Smart Window Air Conditioner is designed to cool large rooms up to approximately 1,560 square feet, making it an excellent choice for spacious bedrooms, living rooms, or apartments. Its strong cooling capacity ensures efficient handling of wide areas. With a SEER rating of 10.3, it offers moderate energy efficiency, helping to keep electricity usage reasonable though it is not the highest rated in efficiency.

A key highlight of this unit is its smart connectivity via LG ThinQ, enabling remote control through a smartphone app or voice assistants like Alexa and Google Assistant, which adds convenience for daily adjustments. The air conditioner operates quietly, with a silent mode around 50 decibels — similar to a quiet conversation — so it should not be disruptive in most environments. It also provides three fan speeds and includes a dehumidification feature, enhancing comfort beyond basic cooling.

Installation is typical for a window unit of this size, with the physical dimensions being notably large, but it does include an installation kit to assist with setup. This LG model is well-suited for users seeking a powerful, smart-controlled window AC for large spaces that balances decent energy efficiency and quiet operation.